1. Field of the Invention
The invention relates to the field of computer graphics and in particular to selecting and manipulating hand drawn shapes within computer graphics software.
2. Related Art
A number of computer graphics programs exist that allow a user to enter drawing material in the form of a sketch, such as Adobe Freehand™. One issue that arises in these programs relates to selecting and manipulating portions of a drawing. Such a selection, at its most crude, might involve creating a box around a portion of the drawing and then doing something with the box, like cutting out a portion of the drawing. Another approach appears in Stiny G, 1976, “Two exercises in formal composition,” Environment and Planning B: Planning and Design 1976 3 187-210. This approach allows a user to select a rectilinear shape within a drawing and manipulate that shape. This document describes a shape computation algorithm to specify the shape, rather than having the user draw a box around the shape.
Known approaches to shape computation and algorithmic art-making within the fields of shape grammars and computer graphics still do not consider the immediacy of the artist's mark in drawing and painting. The drawing and painting space is an expressive and dynamic problem space that is constantly reframed with each successive mark. Moreover, in human drawn sketches, very few—if any—shapes appear that are strictly rectilinear.